A lower part structure for a motorcycle has been known in which a cowl is provided at a lower portion of a vehicle body for guiding airflow (airflow produced by traveling of the vehicle) having flowed past a radiator (see, for example, Japanese Patent Laid-open No. 2008-18904 (FIGS. 1 and 7)).
As shown in Japanese Patent Laid-open No. 2008-18904, a cowling for covering the periphery of a radiator is provided at a front portion of the vehicle. A sub cowling is provided at a lower portion of the vehicle body rearwardly of the cowling, in side view of the vehicle. A front portion of the sub cowling is overlapping with a lower portion of the cowling. The sub cowling includes: left and right inner cowls having side plate portions inclined toward an oblique rear side of the vehicle; and a lower cowl disposed under the inner cowls. The airflow having passed through the radiator is guided toward oblique outer rear sides of the vehicle by the side plate portions of the left and right inner cowls.
In this case, the airflow flowing past the side plate portions of the left and right inner cowls is guided toward oblique rear sides of the vehicle. However, air having passed through the radiator in the center of the vehicle width is liable to be dispersed toward the upper and lower sides and the left and right sides. Thus, there has been room for improvement.